Many methods have been developed for patterning materials on substrates. One method employs a photoresist and a shadow mask, wherein light passes through the shadow mask and selectively exposes the photoresist. The exposed photoresist is then developed and cured to create a patterned photoresist. An etchant that is subsequently applied to the substrate will etch only regions where the photoresist is absent. Alternatively, materials can be deposited on the photoresist and patterned by a lift process, wherein the photoresist swells on application of a solvent, thereby removing the deposited film where the photoresist is present. Additionally, some semiconductor processing materials have been developed with photo-active properties, providing a dielectric material that can be patterned like photoresist; an example is benzocyclo butene (BCB).
In some cases a thin seed layer is patterned, then this layer is plated up to create a thicker layer. This process is well known using copper as the deposition material, for example in the fabrication of printed wiring boards (PWBs).
Methods for etching deposited films include wet etching in a bath of etchant, dry etching using a plasma process in a vacuum, or sputter etching.
Many efforts have been applied to the concept of low cost fabrication of patterned substrates using reel-to-reel processing. Using this method, desired film materials may be deposited on a moving flexible substrate. Some processes such as ink jet printing may be conducted at atmospheric pressure. However, higher quality films may be produced under vacuum. For fabrication of films requiring vacuum processing, a source reel on which the flexible substrate is wound may be moved into a vacuum system for processing, and a take-up reel containing the processed film may be removed when processing is complete. Inside the vacuum chamber the flexible substrate may move serially through multiple processing stations. However, such vacuum systems tend to be expensive, and the parts produced have had a higher fabrication cost than desired.
Accordingly it is desirable to provide a system for fabricating patterned materials on substrates that can be a reel-to-reel system that is operable to produce high quality films without any vacuum required. Such a system may be amenable to automation and may have the potential for low fabrication cost.